This invention relates to a proportional solenoid and more particularly to a pull type proportional solenoid with high force capabilities.
In a typical solenoid valve assembly, the solenoid sub-assembly has an armature which acts on, or is coupled to, a valve member in the valve subassembly. As is known, movement of the armature is responsive to the magnetic flux generated as a result of the electrical current applied to the electromagnetic windings of the solenoid sub-assembly. Thus linear movement of the armature causes corresponding linear movement of the valve member which controls the flow of fluid through the valve. When the armature of the solenoid is connected firmly to the valve member any misalignment therebetween results in loss of operating efficiency. In many different types of solenoids, the overall force being generated by the solenoid is adversely affected by cavities or other voids which typically house springs or the like. One such arrangement is shown in U.S. Pat. No. 5,513,832, issued May 7, 1996 and is assigned to Lectron Products, Inc. In the subject patent, a spring cavity is disposed within the armature 64 and results in the reluctance increasing thus causing the magnetic flux path to degrade thus lessening the maximum operating force output from the solenoid.
The present invention is directed to overcoming one or more of the problems as set forth above.
In an aspect of the present invention a solenoid actuated valve assembly includes a valve assembly including at least a moveable valving element; and a solenoid assembly including an armature. The solenoid assembly is operative to move the armature in response to electrical activation of the solenoid assembly wherein the armature is independently moveable relative to the valving element and the valving element is in tracking engagement with the armature. The valving element is not retained by the solenoid assembly.
The present invention further provides a method of controlling flow through a valve assembly using an electrically activated solenoid assembly, the method including causing movement of armature along a path defined by the solenoid assembly; causing a valving element within the valve assembly to move in a path defined by the valving assembly in response to the activation of the solenoid assembly, the path defined by the solenoid assembly including all paths except a path in alignment with the path defined by the valving assembly; and urging the valving element in abutment with the solenoid assembly to cause a tracking relationship between the armature and the valving element.